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Currently I am working on a prototype project where I try to move a servo (6V) according to the level of light that is recognized by a photodiode making use of the ISR function. A torch light is used as the source of light.

First, I have built this project successfully making use of an arduino uno. After that in order to reduce the energy consumption I have made an Arduino on a breadboard making use of an atmega328 microcontroller adding sleep function using the jeeLib library. It worked well. Now I want to go to the next step with this project to design the prototype into a functional tool/device.

I was planning to customize an arduino and solder the servo (6V), photodiode etc.

I have researched to on this topic and read carefully the following link (How to go from newbie to manufactured?) and learned that creating a customized arduino might emerge to be an exhausting task; especially for a newbie to electronics like me.

At the same I am wondering whether there is a way to skip going through a PCB Fabrication. Now I came to learn that I might use an attiny 85 using a perfboard that can be used to program a servo and ISR function as well. Attiny 85 also consumes less energy.

Given the fact that I 'only' need to control a servo (6V) depending on the voltage going through a photodiode I do think that an attiny85 microcontroller might be a decent way to realize my project with less effort. I am aware of the little EEPROM and Flash size. However as already once in a discussion ( My Atmega328 seems to be overkill, what should I use instead?) apparently not all program that work with arduino uno will work with attiny 85.

Can you tell me whether there is a way for me to skip working with a pcb manufacturer to finalize my project? Is using an attiny 85 microcontroller a good alternative for my project?

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  • \$\begingroup\$ Adafruit trinket adafruit.com/products/1501 , does all the hard work for you and whatever 5V supply you use, your servo should actually still work fine with 5V. \$\endgroup\$
    – KyranF
    May 14, 2015 at 20:35
  • \$\begingroup\$ Another thing you can do to reduce power consumption is use a fixed sampling rate and put the device to sleep between sampling - if you sample at 40Hz for example, to get reasonable response time (you didn't say how fast it had to react to light sources) and the sample time itself is only ten milliseconds or maybe if you need to change output, 100ms, your overall power usage would be halved \$\endgroup\$
    – KyranF
    May 14, 2015 at 20:43
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    \$\begingroup\$ Is this the only device you're ever going to build? Learning to design and build PCBs is a valuable skill. \$\endgroup\$
    – Nick Johnson
    May 14, 2015 at 20:53
  • \$\begingroup\$ @KyranF Thanks for indicateing trinket..it looks interesting! Do you mean I shuold fix the sampling rate of the photodiode? \$\endgroup\$
    – Sathees
    May 14, 2015 at 20:58
  • \$\begingroup\$ How often are you moving the servo? I would think the power the microcontroller consumes is minuscule by comparison. \$\endgroup\$
    – mng
    May 14, 2015 at 20:59

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An attiny will be fine for a single servo and adc sensor with the Arduino firmware. The things an attiny can't do that an atmega can has to do mostly with code space and amount of timers or interrupts. Your project is very small and not affected by this limitation.

As for developing a custom Arduino pcb, it's not that complicated. An Arduino is essentially just a breakout board for the microcontroller, with a regulator and usb to serial circuit attached, neither which are 100% required to be on board. Look at various bare bones Arduino which are no more than the microcontroller and a few passives.

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  • \$\begingroup\$ Thanks for the answer! I have two questions to that. 1. Attiny is however capable of handling interrupts, right? 2. As KyranF suggestet the Adafruit trinket might be an efficient solution for me. What do you think? \$\endgroup\$
    – Sathees
    May 14, 2015 at 21:51
  • \$\begingroup\$ Yes and yes. Ada is a great manufacturer \$\endgroup\$
    – Passerby
    May 14, 2015 at 22:17

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